1. Field
At least some of the various embodiments are directed to systems and methods to selectively radiate and/or receive electromagnetic waves having varying electric field polarizations.
2. Description of the Related Art
Many systems have a need to radiate (i.e., send) or receive electromagnetic waves with varying electric field polarizations (hereafter just polarization). In some systems, radiating or receiving electromagnetic waves with varying polarization dictates having multiple antennas, with each antenna configured to transmit an electromagnetic wave with a particular polarization (e.g. multiple dipole antennas in different physical orientations, multiple patch antennas in different physical orientations).
To provide varying polarizations, other systems use a single patch antenna having multiple active feed points, with all the active feed points used simultaneously to radiate or receive the electromagnetic waves. Radiating electromagnetic waves with patch antennas having multiple active feed points dictates simultaneously generating several phase-delayed versions of the antenna driving signal, with the multiple phase-delayed antenna driving signals applied one each to the multiple feed points. The amount of phase delay and physical spacing of the feed points on the patch antenna control the polarization of the electromagnetic waves transmitted. Receiving electromagnetic waves with patch antenna having multiple active feed points likewise dictates phase-correcting received signals, and conglomerating the phase-corrected signals to produce a received signal that is proportional to the desired polarization. The amount of phase correction applied to each signal and the physical spacing of the feed points on the patch antenna from which the receive signals originate control the polarization to which the patch antenna is most sensitive.